Embodiments relate to an electric device and methods thereof. Some embodiments relate to an image sensor and methods of manufacturing an image sensor.
A photodiode (PD) may be formed by implanting ions into a substrate. As the size of a PD is relatively decreased such that the number of pixels is relatively increased substantially without the increase of a chip size, image quality may be relatively degraded due to an area reduction of a light receiving part. A stack height may not be decreased relative to an area reduction of a light receiving part and the number of photons input into a light receiving part may be relatively decreased due to a diffraction of light called “Airy Disk”.
A PD may be deposited using amorphous silicon (Si). A readout circuitry may be formed on and/or over a Si-substrate through a wafer-to-wafer bonding scheme. A PD may be formed on and/or over a readout circuitry, which may reference a three-dimensional (3-D) image sensor. A PD may be connected to a readout circuitry through a metal line.
After two wafers have been bonded to each other, a process of forming a signal line may be required with respect to a wafer having a photodiode thereover. Although a 3-D device may be realized, light loss may occur due to light reflection caused by a metal line. A ground contact may be formed at a predetermined area of an upper portion of a photodiode. However, a metal line may be required for connection of a ground contact. Since a metal line may cause light reflection, light loss may occur.
Accordingly, there is a need for an image sensor and a method of manufacturing an image sensor which may minimizing light loss, for example by maximizing formation of a signal line.